A thousand miles south of the Rio Grande, Lesly Xiomara Chirinos plodded along a Mexican road comforting her year-old son Murphy, her partner holding up an umbrella to shield them from the punishing sun. On Oct. 13, they abandoned their home in the Honduran city of La Ceiba to join several thousand people on the so-called migrant caravan heading north. Since then, they have been marching for long hours, jumping on pickup trucks, sleeping in parks, living on handouts of food.